Game fails to quit properly

[JCB]

I'm experiencing an issue that has happened to me with quite a few other indie games, especially those developed with XNA.

When I quit the game, Steam says the game is still running, it keeps adding to my played time, and won't allow me to quit (I have to restart my PC to fix this).

My specs are: Vista Ultimate 64-bit, Nvidia GeForce GTX 460, Intel Core 2 Quad Q6600 @2.40GHz, 4 GB RAM.

[JCB]

I still have this issue. Like I said, it's a common problem with most indie games, but it usually is fixed on the first patch or so, but with Unholy Heights it persists.
I have to close Steam using the task manager to fix this, otherwise Steam keeps saying the game is still running, and won't allow me to re-launch the game.

Can you please look into it?